Sodium borohydride → 10-hydroxymethyl-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one

Participants

Reaction Steps

To a suspension of 3 g of 10-hydroxymethylene-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one (mixture of the Z and E forms) in 240 ml of methanol is added 1 g of sodium borohydride portionwise over 10 minutes with stirring, and the stirring is continued at a temperature in the region of 20° C. for 1 hour 30 minutes. A further 1 g of sodium borohydride is added portionwise and the stirring is continued for 30 minutes. The reaction mixture is then filtered and the filter is rinsed with twice 30 ml of methanol. The insoluble material is taken up with 50 ml of water and 4 ml of 1N hydrochloric acid, filtered again, washed with water until neutral and air-dried. The crude product (1 g) is purified by dissolution while hot in 65 ml of dimethylformamide, filtration, addition to the still hot filtrate of 80 ml of methanol and crystallization in an ice-water bath. The crystals obtained are filtered off, washed with twice 15 ml of methanol and dried at 80° C. 0.66 g of 10-hydroxymethyl-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-4-one is thus obtained, in the form of a white solid melting above 260° C. (Analysis % calculated C: 66.40, H: 4.38, N: 16.59, O: 12.63, % found C: 66.4, H: 4.3, N: 16.6, O: 12.1).

Provenance & Evidence